Facility for manufacturing multilayered composite tubes

ABSTRACT

Described is an installation ( 10 ) for producing multi-layer composite tubes ( 116 ). The installation ( 10 ) has a metal strip unwinding device ( 44 ), a metal strip storage device ( 48 ) adjoining the metal strip unwinding device ( 44 ), a metal strip shaping device ( 36 ) adjoining the metal strip storage device ( 48 ), an extruder station ( 12 ) adjoining the metal strip shaping device ( 36 ), and a cooling device ( 50 ) adjoining the extruder station ( 12 ). The metal strip shaping device ( 36 ) serves for shaping the metal strip ( 38 ) which is unwound from the metal strip unwinding device ( 44 ) into a metal tube with overlapping longitudinal edges which are welded to form the metal tube by means of a welding station ( 32 ) at the extruder station ( 12 ). In the extruder station ( 12 ) the metal tube is covered with an inner plastic layer in fixedly adhering relationship and with an outer plastic layer in fixedly adhering relationship. The composite tube produced in that way is cooled to ambient temperature in the cooling device ( 50 ).

The invention concerns an installation for producing multi-layercomposite tubes, comprising a shaping device for shaping a metal stripinto a metal tube with overlapping longitudinal edges, a welding devicefor welding the overlapping longitudinal edges, an extruder station withan extrusion head which adjoins the shaping device and which isconnected to a first extruder for applying an inner plastic layer and asecond extruder for applying an outer plastic layer to the metal tube,and a cooling device for cooling the multi-layer composite tube, whichare arranged in succession in a production line.

Installations of that kind are known per se. In those knowninstallations, the extrusion head is fixedly connected to the firstextruder for the inner plastic layer. The second extruder which isprovided for the outer plastic layer is spatially separated from theunit consisting of the extrusion head and the first extruder and issuitably connected in flow relationship to the extrusion head. Thatstructure adversely affects both the accuracy of assembly and also theproduction speed for producing the multi-layer composite tubes. Afurther deficiency of those known installations is that a change in thecomposite tube nominal size, that is to say converting the installationfrom one composite tube diameter to a desired different composite tubediameter, is possible only at the cost of a considerable amount of timeand assembly complication.

In consideration of those factors the object of the present invention isto provide an installation of the kind set forth in the opening part ofthis specification, which, with a comparatively high production speed,permits optimum composite tube quality, while a change in composite tubenominal size is also possible relatively easily and without taking up agreat deal of time.

In accordance with the invention, in an installation of the kind setforth in the opening part of this specification, that object is attainedin that the extrusion head of the extruder station is disposedstationarily and that the first and the second extruders are arrangedfacing towards each other in mutual alignment in a line laterally besidethe extrusion head in parallel relationship with the production line,wherein the extrusion head in the production line is provided betweenthe first and the second extruders.

In this respect the term ‘production line’ means the line along whichthe metal strip moves along the shaping device for shaping the metalstrip to form the respective metal tube, to the welding device forwelding the overlapping longitudinal edges of the shaped metal strip toform the metal tube, wherein the production line is defined inparticular also by the extruder station, that is to say by the extrusionhead, and thereafter by the cooling device for cooling the producedmulti-layer composite tube. The metal strip or the multi-layer compositetube produced with the installation is moved in a straight line at agiven, comparatively high advance speed through the installation. While,in known installations of the kind set forth in the opening part of thisspecification, with a given composite tube diameter, that is to saynominal size, the advance speed is of the order of magnitude for exampleof 15 m/min, it is possible with the installation according to theinvention and for the same composite tube diameter for the productionspeed to be increased to the order of magnitude of 25 m/min, that is tosay by 67%, in which case that advantage of the installation accordingto the invention involves the advantages of the possibility of a simpleand time-saving change in composite tube diameter with the installationaccording to the invention being of an arrangement which saves on floorarea or space. In particular the fact that, in the installationaccording to the invention, the extrusion head of the extruder stationis stationarily provided alone, that is to say without the firstextruder for the inner plastic layer, and the fact that the first andsecond extruders are provided in alignment with each other in a line inmutually facing relationship laterally beside the extrusion head meansthat the installation is of a design configuration which saves on floorarea, with the advantage that temperature-related changes in length ofthe two extruders are compensated. That has a positive effect on theaccuracy of the installation construction and the accuracy ofmanufacture of the multi-layer composite tubes produced with theinstallation according to the invention.

It has proven to be advantageous if, in the installation according tothe invention, there are third and fourth extruders for bonding agents,wherein the third extruder is associated with the first extruder for theinner plastic layer and the fourth extruder is associated with thesecond extruder for the outer plastic layer of the multi-layer compositetube. It will be appreciated that it would also be possible, in aninstallation according to the invention, for the extruder station to becombined with a single extruder for a bonding agent. That third extruderwould then be combined with a switching device for combining the bondingagent both with the first extruder and with the second extruder in orderto apply the inner plastic layer and the outer plastic layer in firmlyadhering relationship to the metal tube by means of the bonding agent.

The third and the fourth extruders for bonding agent are desirablycardanically mounted to associated stationary column devices. Such astructure correspondingly improves the accuracy of the installation andthe productivity thereof because the adjustability thereof is optimised.

In the installation according to the invention it has proven to beadvantageous if the welding device has a welding station with anultrasound welding wheel, wherein the welding station is displaceable inrespect of height in relation to the extrusion head in a first directionin space parallel to the production line, in a second direction in spaceperpendicular thereto transversely with respect to the production lineand in a third direction in space perpendicular to the first and seconddirections in space, and is pivotable about a pivot axis oriented in thefirst direction in space. That displacement and/or pivotal movement canbe implemented pneumatically or mechanically, for example by spindledrives. That displaceability permits not only a time-saving change innominal size, that is to say the time-saving possibility of convertingthe installation from one composite tube diameter to a desired differentcomposite tube diameter, but it also affords the considerable advantagethat access to the installation is better possible in the case of suchchanges in nominal size or disturbances in production. Possibledisturbances in production can be very rapidly dealt with.

In the installation according to the invention, the ultrasound weldingwheel is desirably connected to a drive motor for controlled rotarydrive of the welding wheel. By means of the drive motor, the speed ofrotation of the ultrasound welding wheel which forms a sonotrode isaccurately matched to the advance speed of the installation, that is tosay the advance speed of the metal strip which is shaped to form themetal tube, in order to produce a highly accurate metal tube which isprovided with the inner and outer plastic layers in firmly adheringrelationship.

To produce the highly precise metal tube from the corresponding metalstrip, it has proven to be desirable if adjacent to the welding deviceare two closing roller devices which each have more than two closingrollers which are distributed at the periphery and which adjoin eachother. Each of the two closing roller devices may have four mutuallyadjoining closing rollers.

In order to permit adaptation to different material qualities of metalstrips which are to be shaped to form the metal tube, in respect ofdimensional tolerances, stiffnesses of the material and so forth, it isdesirable if at least some of the closing rollers of the respectiveclosing roller device are radially displaceable.

In accordance with the invention, a precise change in composite tubenominal size is permitted in a still further better fashion if, in theinstallation according to the invention, the shaping device has a baseelement on which pairs of shaping rollers are arranged in succession ata spacing from each other in the advance direction of the metal strip tobe shaped, wherein the base element is displaceable in the seconddirection in space transversely with respect to the production line andin the third direction in space vertically and is pivotable about apivot axis oriented in the second direction in space and about a pivotaxis oriented in the third direction in space. Such a linear andvirtually cardamic arrangement of the base element means that the pairsof shaping rollers provided thereon are precisely adjustable in such afashion as to save time, which has an advantageous effect on the levelof productivity of the installation according to the invention. Inaddition, by virtue of this design configuration of the last-mentionedkind, it is also easily possible for the shaping device to be veryquickly and accurately converted and set to the respective metal stripwidth and thus to the desired tube diameter. In this case adjustingwheels can be provided for displacement in the second direction in spaceand about the pivot axis oriented in the second direction in space, andfor displacement in the third direction in space and about the pivotaxis oriented in the third direction in space. The adjusting wheels maybe for example hand wheels in order to implement suitable manualadjustment.

In the installation according to the invention arranged upstream of theshaping device in the production direction is a metal strip unwindingdevice which is displaceable in the second direction in spacetransversely with respect to the production line.

That transverse displaceability of the metal strip unwinding devicemeans that it is advantageously easily possible for the metal stripunwinding device to be accurately set in dependence on the width of therespective metal strip to be processed, that is to say the metal stripunwinding device and thus the respective metal strip can be centeredaccurately, that is to say exactly, in relation to the production line.That centering displacement of the metal strip unwinding device ispossible in a simple fashion and in such a way as to save a great dealof time.

The metal strip unwinding device may have a single reel mounting for ametal strip reel, but it is preferred if the metal strip unwindingdevice has a support element with two reel mountings, wherein thesupport element is rotatable about a vertical axis and the two reelmountings are provided at mutually remote sides of the support element.In comparison with a metal strip unwinding device having a single reelmounting, such a design configuration of the last-mentioned kind enjoysthe advantage that it is possible to change from an exhausted metalstrip reel to an unused fresh metal strip reel in such a way as to savetime. That also has an advantageous effect on the level of productivityof the installation according to the invention.

Particularly if, in the installation according to the invention, themetal strip unwinding device has a support element with a single reelmounting, it is desirable If provided between the metal strip unwindingdevice and the metal strip shaping device is a metal strip storagedevice which has vertical side walls arranged parallel to each other andto the production line, because it is possible for a suitable endportion or a residual length of the exhausted metal strip reel to bedeposited in that metal strip storage device and for the end of thatexhausted metal strip to be fixedly connected to the beginning of afresh metal strip reel. During that operation of joining the two ends,which is desirably effected by ultrasonic welding, the residue of themetal strip, which is in the metal strip storage device, can becontinuously subjected to further processing to form the multi-layercomposite tube. In that respect, the vertical side walls of the metalstrip storage device which are arranged parallel to each other and tothe production line provide a guidance effect for the stored length ofmetal strip.

From the point of view of being able to process metal strips ofdifferent strip widths with a high level of productivity on theInstallation according to the invention, it is desirable if the sidewalls of the metal strip storage device are simultaneously displaceablesymmetrically in mirror-image relationship with respect to theproduction line. That displacement can be effected for example by meansof a hand wheel which is suitably combined with the two side walls ofthe metal strip storage device. That can be effected for example byspindle drives and a belt or the like which drives the spindles incommon relationship.

In order to provide for cooling of the corresponding initial portion ofthe multi-layer composite tube even during each start-up phase ofoperation of the installation according to the invention, that is to sayduring the operation of filling the cooling device with the coolingliquid, it is desirable if, in the installation according to theinvention, the cooling device has an elongate liquid bath with a nozzledevice and with composite tube hold-down devices, wherein the nozzledevice is formed with mutually spaced nozzle openings which are directedtowards the production line. The nozzle openings which are orientedtowards the production line, that is to say the multi-layer compositetube, provide that the cooling liquid is already directed during theoperation of filling the liquid bath towards the leading-end or initialportion of the multi-layer composite tube in order to produce a suitablecooling effect. The multi-layer composite tube is positioned in adefined fashion in the elongate liquid bath of the cooling device bymeans of the composite tube hold-down devices, that is to say themulti-layer composite tube is prevented from floating up in the liquidbath. Such a floating effect would be caused by the buoyancy action ofthe multi-layer composite tube, without the use of the composite tubehold-down devices. That buoyancy action results from the fact that thereis a corresponding increased pressure in the interior of the multi-layercomposite tube. That increased pressure is necessary in order toprecisely form the metal tube with the inner plastic layer firmlyadhering thereto.

The respective composite tube hold-down device can have two mutuallyspaced rollers which are mounted on a pivotal lever. Such a per se knowndesign configuration affords the advantage that metal-layer compositetubes of different nominal diameters can be readily precisely correctlypositioned in the elongate liquid bath of the cooling device.

The above-mentioned increased pressure in the interior of themulti-layer composite tube can be produced in per se known manner by amandrel or bar, as is described for example in EP 0 581 208 B1. In thecase of the installation according to the invention, it has been foundto be desirable to provide in the liquid bath a tube clamping-off devicewith squeeze-off jaws, which device can be reciprocated along the liquidbath, and to provide at the beginning of the liquid bath a firstactuating device for closing the squeeze-off jaws and for keeping themclosed and at the end of the elongate liquid bath a second actuatingdevice for opening the squeeze-off jaws and for keeping them open. Themulti-layer composite tube produced in the installation is squeezed offat a given location by means of the squeeze-off jaws of the tubeclamping-off device, with the interior of the tube being closed by theinner plastic layer which is still in a plastic condition at thatlocation. That makes It possible to produce a suitable increasedpressure in the interior of the tube. In the installation according tothe invention, the tube clamping-off device with the squeeze-off jawscan be reciprocated in the elongate liquid bath by electric motor means.The forward movement between the first and second actuating devices iseffected in that respect at a speed adapted to the advance speed of themulti-layer composite tube produced in the installation. The returnmovement from the second actuating device to the first actuating devicecan also be effected at a higher speed.

In the installation according to the invention, it is desirable ifdisposed downstream of the cooling device in the production direction isan optical tube monitoring device, a printer, a tube draw-off device anda tube winding-up device. The optical outer tube monitoring device canhave a number of video cameras. The video cameras are connected togetherand combined with a control device of the installation according to theinvention in such a way that the installation is immediately stopped ifthe video cameras detect production defects on the produced multi-layercomposite tube.

The installation according to the invention can be precisely set up in arelatively simple fashion without entailing a great deal of time, ifthere is provided a two-part base device having a first and a secondbase portion, wherein arranged on the first base portion are the metalstrip unwinding device, the metal strip storage device and the extruderstation, and arranged on the second base portion are the optical tubemonitoring device, the printer, the tube draw-off device and the tubewinding-up device, wherein the first and second base portions areconnected together by means of the cooling device. The first and secondbase portions can be in the form of base plates with suitable cavitiesor shafts—virtually like palettes—in order also to serve to receive theinstallation materials of the installation according to the invention.

Further details, features and advantages will be apparent from thedescription hereinafter of an embodiment illustrated in the drawing ofthe installation according to the invention for producing multi-layercomposite tubes. In the drawing:

FIG. 1 is a side view of an embodiment of the installation,

FIG. 2 is a view from above of the installation shown in FIG. 1,

FIG. 3 is a side view of an embodiment of the metal strip storage deviceof the installation shown in FIGS. 1 and 2,

FIG. 4 is a plan view of the metal strip storage device shown in FIG. 3,

FIG. 5 is a cut-away front view of the metal strip storage device shownin FIGS. 3 and 4,

FIG. 6 is a view of the metal strip storage device viewing in thedirection of the arrows VI—VI in FIG. 3,

FIG. 7 is a partially cut-away view of part of an embodiment ofessential portions of a shaping device of the installation shown inFIGS. 1 and 2 in a side view,

FIG. 8 is a view in section taken along line VIII—VIII in FIG. 7,

FIG. 9 is a view in section taken along line IX—IX in FIG. 7,

FIG. 10 is a sectional view of a first closing roller device of theinstallation shown in FIGS. 1 and 2,

FIG. 11 is a sectional view similar to FIG. 10 of a second closingroller device of the installation shown in FIGS. 1 and 2,

FIG. 12 is a front view of an embodiment of a tube clamping-off deviceprovided in a liquid bath of the installation shown in FIGS. 1 and 2,with squeeze-off jaws which are shown in solid lines in the closedsqueeze-off position and in broken lines in the opened return transportposition,

FIG. 13 is a plan view of a first base portion of a two-part base deviceof the installation shown in FIGS. 1 and 2,

FIG. 14 is a view of the base portion of FIG. 13 viewing in thedirection of the arrow XIV, and

FIG. 15 is a partly cut-away view of the second base portion of FIG. 13viewing in the direction of the arrow XV.

FIGS. 1 and 2 are a side view and a view from above of an embodiment ofthe installation 10 for producing multi-layer composite tubes. Theinstallation 10 has an extruder station 12 which forms the heart of theinstallation 10. The extruder station 12 has a stationary extrusion head14 which determines a location of a production line 16 of theinstallation 10, as indicated by a dash-dotted line. Associated with theextrusion head 14 is a first extruder 18 and a second extruder 20. Thefirst extruder 18 serves for the production of an inner plastic layerand the second extruder serves for the production of an outer plasticlayer on a metal tube. The first and second extruders 18 and 20 areprovided laterally beside the production line 16 in parallelrelationship therewith and are arranged facing towards each other. Theextrusion head 14 is disposed centrally and laterally displaced betweenthe first and second extruders 18 and 20. As can be clearly seen fromFIG. 2 such an arrangement saves space and floor area.

So that the inner plastic layer and the outer plastic layer can beapplied in firmly adhering relationship to the metal tube, the extruderstation 12 has a third extruder 22 and a fourth extruder 24 for bondingagent, which like the first and second extruders 18 and 20 are connectedto the stationarily provided extrusion head 14 of the extruder station12. The third and fourth extruders 22 and 24 are cardanically mounted toassociated column elements 26 and are thus simply precisely adjustablein relation to the extrusion head 14. The third and fourth extruders 22and 24 are disposed on the same side of the production line 16 as thefirst and second extruders 18 and 20 so that access to the extrusionhead 14 is advantageously possible without any problem.

The production direction of the installation 10 is indicated by thearrow 28 in FIGS. 1 and 2. Associated with the extrusion head 14 is awelding device 30 of a welding station 32 which has an ultrasoundwelding wheel which is controlledly driven by a drive motor 34. Theultrasound welding wheel is displaceable as desired in relation to theextrusion head 14 in a first direction x in-space parallel to theproduction line 16 and in a second direction y in space which isperpendicular to the first direction x. The first direction in spacewhich is indicated by the double-headed arrow x is in the plane of thedrawing in FIG. 1 and in the plane of the drawing in FIG. 2. The seconddirection y in space which is perpendicular thereto is in the plane ofthe drawing in FIG. 2 and is oriented perpendicularly to the plane ofthe drawing in FIG. 1. The second direction y in space is thereforeoriented in a horizontal plane transversely with respect to theproduction line 16. In FIG. 1 a vertical direction z in space which isperpendicular to the first and second directions x and y is indicated bya corresponding double-headed arrow. The third direction z in space isoriented perpendicularly to the plane of the drawing in FIG. 2 and is inthe plane of the drawing in FIG. 1. The ultrasound welding wheel of thewelding device 30 is not only linearly displaceable in the firstdirection x and in the second direction y, as has already been statedabove, but it is also pivotable as desired about a pivot axis orientedin the second direction y in space. The welding device 30 is thereforeadvantageously highly mobile and consequently can be very exactlyarranged on the production line.

Provided upstream of the welding station 32 in the production directionindicated by the arrow 28 is a metal strip shaping station 36 whichserves to shape a metal strip 38 (see FIG. 1) into the form of a metaltube. The metal strip 38 which is to be shaped into the metal tube isunwound from a reel 40 which is provided on a reel mounting 52 of ametal strip unwinding device 44. The metal strip unwinding device 44 hasa support element 46 which has two reel mountings 42. The two reelmountings 42 are disposed in diametrally opposite relationship, as canbe seen from FIG. 2. The one reel mounting 42 is disposed on theproduction line 16 and the second reel mounting is disposed outside theproduction line 16 and can be fitted with an unused fresh metal stripreel during the unwinding of the metal strip reel which is on theproduction line 16. The support element 46 of the metal strip unwindingdevice 44 is adjustable in the second direction y in space in order toprovide for alignment of the corresponding reel mounting 42 in relationto the production line 16.

A metal strip storage device 48 is disposed between the metal stripunwinding device 44 and the shaping device 36. As can be seen from FIG.1 the metal strip storage device 48 is provided for the intermediatestorage in particular of an end portion of an exhausted metal strip reel40, to arrange an unused fresh metal strip reel in the production line16, and to mechanically fixedly connect the leading end portion of thewinding of the unused fresh metal strip reel to the end of the exhaustedmetal strip reel, without having to stop the installation. During thatoperation of connecting the above-mentioned ends of the strips thecorresponding portion of the metal strip 38 is taken from the metalstrip storage device 48.

Downstream of the extruder station 12 the installation 10 has a coolingdevice 50 with an elongate liquid bath 52. Arranged downstream of theliquid bath 52 of the cooling device 50 in the production direction 28is an optical tube monitoring device 54, a printer 56, a tube draw-offdevice 58 and a tube winding-up device 60.

The metal strip unwinding device 46, the metal strip storage device 48and the extruder station 12 are arranged on a first base portion 62. Theoptical tube monitoring device 54, the printer 56, the tube draw-offdevice 58 and the tube winding-on device 60 are arranged on a secondbase portion 64. The first and second base portions 62 and 64 form atwo-part base device 66. The first and second base portions 62 and 64are spaced from each other and are connected together by the coolingdevice 50.

FIGS. 3, 4, 5 and 6 show an embodiment of the metal strip storage device48 with a drive or braking device 68 with two rollers 70, between whichthe metal strip 38 which is to be shaped to form a metal tube (seeFIG. 1) is moved in a defined fashion. The metal strip storage device 48has two mutually parallel vertical side walls 72 which aresimultaneously displaceable in mirror image relationship with theproduction line 16 (see FIG. 4) in order to adapt the internal spacingbetween the two side walls 72 to the width of the respective metal strip38. A hand wheel 74 which is connected to an endless belt 76 serves fordefined displacement as desired of the two side walls 72. The endlessbelt 76 is passed around four screw spindles 78 which respectively havea right-hand screwthread and spaced therefrom a left-hand screwthread.The right-hand screwthread portion and the left-hand screwthread portionare respectively screwed through an associated nut element 80 fixed tothe corresponding side wall 72. The endless belt 76 is for example atoothed belt which is passed around toothed pulleys 82 secured to thescrew spindles 78. When the hand wheel 74 is rotated the screw spindles78 are simultaneously driven by means of the endless belt 76, involvinga screw movement of the screw spindles 78 through the nut elements 80and consequently a simultaneous movement of the two vertical side walls72 of the metal strip storage device 48 towards or away from each other.The lateral spacing of the two side walls 72 with respect to the centralproduction line 16 therefore remains constant, that is to say,irrespective of the respective internal distance between the two sidewalls 72 the production line 16 is precisely in the center between thetwo side walls 72.

FIGS. 7, 8 and 9 show an embodiment of a base element 84 of the shapingdevice 36 of the installation 10. The base element 84 has a profileelement 86 which is shown in cut-away form in FIG. 7, withlongitudinally channels 88 (see FIGS. 8 and 9). Pairs of shaping rollers(not shown) are arranged displaceably in the first direction x in spacein per se known manner on the base element 84. The base element 84 isprovided on mounting devices 88. Each of the two mounting devices 88 hasa hand wheel 90 for adjustment of the base element 84 in the thirddirection z in space and a hand wheel 92 for adjustment of the baseelement 84 in the second direction y in space, wherein suitableactuation of the one and/or the other hand wheel 90, 92 of the oneand/or the other mounting device 88 not only permits linear adjustmentin the second and/or third directions y and/or z, but in addition thebase element 84 of the shaping device 36 can be pivoted as desired abouta pivot axis oriented in the second direction y and/or about a pivotaxis oriented in the third direction z in order to permit exactalignment of the base element 84 in relation to the production line 16.

FIG. 10 is a sectional view of an embodiment of a closing roller device94 which is arranged adjacent to the welding device 30 of theinstallation 10. FIG. 11 is a sectional view similar to FIG. 10 showinga second closing roller device 96 which is arranged in the productiondirection downstream of the first closing roller device 94 in theproduction line 16. Each of the two closing roller devices 94 and 96 hasclosing rollers 98 which are mutually adjoining. The closing rollers 98of the first closing roller device 94 establish a spiral contour whichis matched to the spiral shape of the metal tube preform or blank. Theclosing rollers 98 of the second closing roller device 96 define theoutside diameter of the metal strip 38 which has been shaped to form themetal tube, with mutually overlapping longitudinal edges. A part of theclosing rollers 98 of the first and second closing roller devices 94 and96 are radially displaceable in relation to the production line 16. Forthat purpose they are mounted eccentrically at adjustment spindles 102.

FIG. 12 is a cut-open end view of the liquid bath 52 of the coolingdevice 50. Arranged in the elongate liquid bath 52 is a tubeclamping-off device 104 which is displaceable with a reciprocatingmovement in the longitudinal direction of the liquid bath 52, that is tosay perpendicularly to the plane of the drawing in FIG. 12. For thatpurpose, the tube clamping-off device 105 is connected to a drive 106 byway of an endless drive belt 108. A first actuating device 110 isarranged at the beginning of the elongate liquid bath 52. A secondactuating device 112 is arranged at the end of the elongate liquid bath52. The first actuating device 110 is provided to move the squeeze-offjaws 114 of the tube clamping-off device 104 towards each other in theproduction line 16 in order to squeeze off and close the metal compositetube 116 disposed between them. The squeeze-off jaws 114 then remainclosed, that is to say, they move, clamped to the metal composite tube,with the metal composite tube as it advances along the production line16. When, at the end of the elongate liquid bath 52, the tubeclamping-off device 104 reaches the second actuating device 52, then bymeans thereof the squeeze-off jaws 114 of the tube clamping-off device104 are opened, whereupon the tube clamping-off device 106 is moved backagain by means of the drive 106 into its initial position, that is tosay at the beginning of the elongate liquid bath 52. The tubeclamping-off device 104 therefore performs so-to-speak a pilgrim-typestepping movement.

FIG. 13, 14 and 15 show an embodiment of the first base portion 62 ofthe two-part base device 66 of the installation 10 shown in FIGS 1 and2. A base plate 118 is displaceable definedly as desired on the baseportion 62 in the second direction y in space by means of a hand wheel120 in order to align the support element 46, which is fixed on the baseplate 118, of the metal strip unwinding device 44 (see FIGS. 1 and 2),that is to say the corresponding side 40, exactly with respect to theproduction line 16.

What is claimed is:
 1. An installation for producing multi-layercomposite tubes (16), comprising a shaping device (36) for shaping ametal strip (38) into a metal tube with overlapping longitudinal edges,a welding device (30) for welding the overlapping longitudinal edges, anextruder station (12) with an extrusion head (14) which adjoins theshaping device (36) and which is connected to a first extruder (18) forapplying an inner plastic layer and a second extruder (20) for applyingan outer plastic layer to the metal tube, and a cooling device (50) forcooling the multi-layer composite tube (116) produced, wherein theextrusion head (14) of the extruder station (12) is disposedstationarily and the first and the second extruders (18 and 20) arearranged in mutual alignment in a line laterally beside the extrusionhead (14) in parallel relationship with the production line (16),wherein the extrusion head (14) in the production line (16) is providedbetween the first and the second extruders (18, 20), characterised inthat a third and a fourth extruder (22 and 24) for bonding agent aremounted to associated stationary column devices (26), wherein the thirdextruder (22) is associated with the first extruder (18) and the fourthextruder (24) is associated with the second extruder (20), and furthercharacterised in that arranged adjacent to the welding device (30) aretwo closing roller devices (94, 96) which each have more than twoclosing rollers (98) which are distributed at the periphery and whichmutually adjoin.
 2. An installation as set forth in claim 1characterised in that at least two of the closing rollers (98) of therespective closing roller device (94, 96) are radially adjustable.
 3. Aninstallation for producing multi-layer composite tubes (16), comprisinga shaping device (36) for shaping a metal strip (38) into a metal tubewith overlapping longitudinal edges, a welding device (30) for weldingthe overlapping longitudinal edges, an extruder station (12) with anextrusion head (14) which adjoins the shaping device (36) and which isconnected to a first extruder (18) for applying an inner plastic layerand a second extruder (20) for applying an outer plastic layer to themetal tube, and a cooling device (50) for cooling the multi-layercomposite tube (116) produced, wherein the extrusion head (14) of theextruder station (12) is disposed stationarily and the first and thesecond extruders (18 and 20) are arranged in mutual alignment in a linelaterally beside the extrusion head (14) in parallel relationship withthe production line (16), wherein the extrusion head (14) in theproduction line (16) is provided between the first and the secondextruders (18, 20), characterised in that a third and a fourth extruder(22 and 24) for bonding agent are mounted to associated stationarycolumn devices (26), wherein the third extruder (22) is associated withthe first extruder (18) and the fourth extruder (24) is associated withthe second extruder (20), further characterised in that arrangedadjacent to the welding device (30) are two closing roller devices (94,96) which each have more than two closing rollers (98) which aredistributed at the periphery and which mutually adjoin, and furthercharacterised in that the shaping device (36) has a base element (84) onwhich pairs of shaping rollers are arranged in succession at mutualspacings in the advance direction of the metal strip (38) to be shaped,wherein the base element (84) is displaceable in a transverse directionand a vertical direction with respect to the production line (16) and ispivotable about a pivot axis oriented in the transverse direction andabout a pivot axis oriented in the vertical direction.
 4. Aninstallation as set forth in claim 3 characterised in that the weldingdevice (30) has a welding station (32) with an ultrasound welding wheel,wherein the welding station (32) is displaceable with respect to theextrusion head (14) in a first direction in space (x) parallel to theproduction line (16), in a second direction in space (y) perpendicularthereto transversely with respect to the production line (16) and in athird direction in space (z) perpendicular to the first and the seconddirections in space (x and y) and is pivotable about a pivot axisoriented in the first direction in space (x).
 5. An installation as setforth in claim 4 characterised in that the ultrasound welding wheel isconnected to a drive motor (34) for the controlled rotary drive thereof.6. An installation for producing multi-layer composite tubes (16),comprising a shaping device (36) for shaping a metal strip (38) into ametal tube with overlapping longitudinal edges, a welding device (30)for welding the overlapping longitudinal edges, an extruder station (12)with an extrusion head (14) which adjoins the shaping device (36) andwhich is connected to a first extruder (18) for applying an innerplastic layer and a second extruder (20) for applying an outer plasticlayer to the metal tube, and a cooling device (50) for cooling themulti-layer composite tube (116) produced, wherein the extrusion head(14) of the extruder station (12) is disposed stationarily and the firstand the second extruders (18 and 20) are arranged in mutual alignment ina line laterally beside the extrusion head (14) in parallel relationshipwith the production line (16), wherein the extrusion head (14) in theproduction line (16) is provided between the first and the secondextruders (18, 20), characterised in that a third and a fourth extruder(22 and 24) for bonding agent are mounted to associated stationarycolumn devices (26), wherein the third extruder (22) is associated withthe first extruder (18) and the fourth extruder (24) is associated withthe second extruder (20), and further characterized in that the shapingdevice (36) has a base element (84) on which pairs of shaping rollersare arranged in succession at mutual spacings in the advance directionof the metal strip (38) to be shaped, wherein the base element (84) isdisplaceable in a transverse direction and a vertical direction withrespect to the production line (16) and is pivotable about a pivot axisoriented in the transverse direction and about a pivot axis oriented inthe vertical direction.
 7. An installation as set forth in claim 6characterised in that adjusting wheels (90, 92) are provided fordisplacement in the transverse direction and about the pivot axisoriented in the transverse direction and for displacement in thevertical direction and about the pivot axis oriented in the verticaldirection.
 8. An installation as set forth in claim 3 characterised inthat arranged upstream of the shaping device (36) in the productiondirection is a metal strip unwinding device (44) which is displaceablein a transverse direction with respect to the production line (16). 9.An installation as set forth in claim 8 characterised in that the metalstrip unwinding device (44) has a support element (46) with two reelmountings (42), wherein the support element (46) is rotatable about avertical axis and the two reel mountings (42) are provided at mutuallyremote sides of the support element (46).
 10. An installation forproducing multi-layer composite tubes (16), comprising a shaping device(36) for shaping a metal strip (38) into a metal tube with overlappinglongitudinal edges, a welding device (30) for welding the overlappinglongitudinal edges, an extruder station (12) with an extrusion head (14)which adjoins the shaping device (36) and which is connected to a firstextruder (18) for applying an inner plastic layer and a second extruder(20) for applying an outer plastic layer to the metal tube, and acooling device (50) for cooling the multi-layer composite tube (116)produced, wherein the extrusion head (14) of the extruder station (12)is disposed stationarily and the first and the second extruders (18 and20) are arranged in mutual alignment in a line laterally beside theextrusion head (14) in parallel relationship with the production line(16), wherein the extrusion head (14) in the production line (16) isprovided between the first and the second extruders (18, 20), andfurther characterised in that a third and a fourth extruder (22 and 24)for bonding agent are mounted to associated stationary column devices(26), wherein the third extruder (22) is associated with the firstextruder (18) and the fourth extruder (24) is associated with the secondextruder (20), further characterised in that a metal strip unwindingdevice (44) has a support element (46) with two reel mountings (42),wherein the support element (46) is rotatable about a vertical axis andthe two reel mountings (42) are provided at mutually remote sides of thesupport element (46), and further characterised in that provided betweenthe metal strip unwinding device (44) and the metal strip shaping device(36) is a metal strip storage device (48) which has two vertical sidewalls (72) which are arranged parallel to each other and to theproduction line (16).
 11. An installation as set forth in claim 10characterised in that the two side walls (72) of the metal strip storagedevice (48) are simultaneously displaceable symmetrically inmirror-image relationship with respect to the production line (16). 12.An installation as set forth in claim 3 characterised in that thecooling device (50) has an elongate liquid bath (52) with a nozzledevice and with composite tube hold-down devices, wherein the nozzledevice is formed with mutually spaced nozzle openings which are directedtowards the production line (16).
 13. An installation as set forth inclaim 12 characterised in that the respective composite tube hold-downdevice has two mutually spaced rollers which are mounted on a pivotallever.
 14. An installation for producing multi-layer composite tubes(16), comprising a shaping device (36) for shaping a metal strip (38)into a metal tube with overlapping longitudinal edges, a welding device(30) for welding the overlapping longitudinal edges, an extruder station(12) with an extrusion head (14) which adjoins the shaping device (36)and which is connected to a first extruder (18) for applying an innerplastic layer and a second extruder (20) for applying an outer plasticlayer to the metal tube, and a cooling device (50) for cooling themulti-layer composite tube (116) produced, wherein the extrusion head(14) of the extruder station (12) is disposed stationarily and the firstand the second extruders (18 and 20) are arranged in mutual alignment ina line laterally beside the extrusion head (14) in parallel relationshipwith the production line (16), wherein the extrusion head (14) in theproduction line (16) is provided between the first and the secondextruders (18, 20), characterised in that a third and a fourth extruder(22 and 24) for bonding agent are mounted to associated stationarycolumn devices (26), wherein the third extruder (22) is associated withthe first extruder (18) and the fourth extruder (24) is associated withthe second extruder (20), further characterized in that the coolingdevice (50) has an elongate liquid bath (52) with a nozzle device andwith composite tube hold-down devices, wherein the nozzle device isformed with mutually spaced nozzle openings which are directed towardsthe production line (16), and further characterised in that provided inthe liquid bath (52) is a tube clamping-off device (104) which isreciprocatable along the liquid bath (52) and has squeeze-off jaws(114), and that provided at the beginning of the liquid bath (52) is afirst actuating device (110) for closing and keeping closed thesqueeze-off jaws (114) and provided at the end of the liquid bath (52)is a second actuating device (112) for opening and for keeping open thesqueeze-off jaws (114).
 15. An installation as set forth in claim 3characterised in that provided downstream of the cooling device (50) inthe production direction (28) is an optical tube monitoring device (54),a printer (56), a tube draw-off device (58) and a tube winding-on device(60).
 16. An installation as set forth in claim 15 characterised in thatthe optical tube monitoring device (54) has a number of video cameras.17. An installation for producing multi-layer composite tubes (16),comprising a shaping device (36) for shaping a metal strip (38) into ametal tube with overlapping longitudinal edges, a welding device (30)for welding the overlapping longitudinal edges, an extruder station (12)with an extrusion head (14) which adjoins the shaping device (36) andwhich is connected to a first extruder (18) for applying an innerplastic layer and a second extruder (20) for applying an outer plasticlayer to the metal tube, and a cooling device (50) for cooling themulti-layer composite tube (116) produced, wherein the extrusion head(14) of the extruder station (12) is disposed stationarily and the firstand the second extruders (18 and 20) are arranged in mutual alignment ina line laterally beside the extrusion head (14) in parallel relationshipwith the production line (16), wherein the extrusion head (14) in theproduction line (16) is provided between the first and the secondextruders (18, 20), characterised in that a third and a fourth extruder(22 and 24) for bonding agent are mounted to associated stationarycolumn devices (26), wherein the third extruder (22) is associated withthe first extruder (18) and the fourth extruder (24) is associated withthe second extruder (20), and further characterised in that there isprovided a two-part base device (66) comprising a first base portion(62) and a second base portion (64), wherein arranged on the first baseportion (62) are a metal strip unwinding device (44), a metal stripstorage device (48) and the extruder station (12), arranged on thesecond base portion (64) are an optical tube monitoring device (54), aprinter (56), a tube draw-off device (58) and a tube winding-on device(60), and the first and second base portions (62, 64) are connectedtogether by means of the cooling device (50).